Show me your socks, and I'll tell if if you have a tear
Make sure all your socks are perfect!
When in Japan, there will be many occasions to take your shoes off:
visiting a lab? take off your shoes
a temple: off they go
a Japanese restaurant: all shoes stay at the entrance
Japanese people are socks freaks. They have all kind of colors and patterns. 5 fingers's socks, tabi-esque 2 fingered socks, only fingers socks to use with sandals, lacy socks, leg warmers, they even have normal socks. With socks, Japanese people are very creative, some might think, well, eccentric.
So, you can wear any socks you like. No problem at all.
The point is: make sure you do not wear socks of different colors, or socks with tears (snags?).
Don't forget to check your nail polish (if you are a girl)
Make sure that your socks will not destroy your reputation!
In exchange, you will get slippers.
Usually in plastic. And the slippers will definitely kill your reputation!